Obesity, like its leaner and infamous counterpart–wasting, is one of the extremes of malnutrition. Though it doesn't receive as much attention as disorders in the protein energy malnutrition (PEM) spectrum, it is a weighty public health challenge, affecting both high, mid, and low-income countries. According to the WHO, over 4 million people die annually as a result of being obese or overweight.

WHAT DO OVERWEIGHT AND OBESITY MEAN?

Overweight and obesity are defined as the excessive and abnormal accumulation of fat in the body that poses a health risk.

HOW DOES ONE KNOW IF ONE IS OVERWEIGHT OR OBESE?

The appropriateness of an individual's weight can be objectively assessed using a simple measurement known as the Body Mass Index (BMI). The BMI is the ratio of the body mass (weight) in Kilograms to the square of the body height in meters. Mathematically, it is expressed as:

BMI = Weight (Kg)/Height² (m²)

The normal BMI lies between 18.5–24.9. A BMI within the range of 25.0 to 29.9 is considered overweight. One is said to be obese if the BMI is 30.0 or higher.

Another important indicator of obesity is waist size. Waist size is measured with tape from the top of the hip bone to the belly button and round. Regardless of BMI, a waist size of 35 inches or higher in women and of 40 inches or higher in men (abdominal obesity) are health risks.

WHAT ARE THE CAUSES OF OBESITY?

Obesity may result from the following:

• High intake of calories
• Sedentary lifestyle
• Genetics
• Medications (steroids, antidepressants, anticonvulsants)
• Health conditions (Polycystic ovarian syndrome, Cushing's syndrome, hypothyroidism)
• Stress, emotional factors (depression), and poor sleep.

WHAT ARE THE HEALTH IMPLICATIONS OF OBESITY?

A common joke amongst medical students is that if during exams one is at a loss of what to write as a risk factor for a particular health condition, one can never go wrong with smoking and obesity. Obesity is the Pandora's box of the 21st century. The following are some of the health conditions one is predisposed to by being overweight or obese:

• Type 2 Diabetes
• Heart disease and stroke
• Hypertension
• Gallbladder disease
• Osteoarthritis
• Gout
• Sleep apnea
• Dyslipidemia
• Fatty liver disease
• Certain cancers (breast, ovarian, colorectal, thyroid, multiple myeloma, etc.)
• etc.

Obesity is a pandemic; one that demands attention commensurate to the burden it places on public health. The subsequent post will be a session that explores weight loss.

Watch this space.